Replace the [bracketed] placeholders with your own details - or open it in the editor and do it there. Switch levels to see the letter rewritten for junior and senior applicants.
Dear Hiring Manager,
I am writing to apply for the Software Engineer position at [Company Name]. Over the past five years I have designed, built, and operated backend services that customers rely on every day, most recently at a logistics platform where my team's order-routing service processed more than two million shipments a month. This role appeals to me because it combines the two things I care most about: shipping product quickly and keeping systems dependable at scale.
In my current position at [Current Company], I own three production services written in TypeScript and Go. Last year I led the migration of our billing pipeline from a nightly batch job to an event-driven architecture, which cut invoice processing time from six hours to under ten minutes and reduced support tickets about billing delays by 40 percent. I also introduced contract testing between our services, which caught integration regressions before deployment and halved production incidents over two quarters.
Beyond the code itself, I work to make the people around me faster. I mentor two junior engineers, run our weekly architecture review, and wrote the onboarding guide that new backend hires still use today. I believe the best engineering teams treat clarity - in code, in documentation, and in communication - as a feature, and I try to contribute to that wherever I work.
What draws me to [Company Name] specifically is the engineering team's public writing about your move toward event-driven services. That is exactly the transition I have just carried a team through, and I would welcome the chance to bring those lessons - including the mistakes we made - to your roadmap.
Thank you for your time and consideration. I would be glad to walk through any of these projects in more detail.
Sincerely,
[Your Name]
Run your finished letter through these checks before you send it.
The first paragraph carries scope, not adjectives
Instead of calling itself passionate, the opening names what the writer's service does - order routing for more than two million shipments a month. A hiring manager knows within one sentence what size of system this candidate has kept alive.
One migration story does the work of a keyword list
The billing pipeline paragraph has a before, an after, and a consequence: six hours to under ten minutes, and fewer support tickets. That shape is what makes a story credible - anyone can claim event-driven experience, few can describe what changed because of it.
It shows the part of seniority that is not code
Mentoring, the weekly architecture review, and the onboarding guide tell a lead that this person raises the team's output, not only their own. That is the difference between a mid-level and a senior hire, and it belongs in the letter because a resume rarely has room for it.
The company paragraph proves the letter was written once
Referencing the team's public writing about event-driven services - and offering the mistakes as well as the wins - is something a mass-mailed letter cannot contain. It also sets up the interview conversation the writer wants to have.
Replace the migration with your own largest change
It does not have to be architecture. A test suite that cut deploy fear, a rewrite of a flaky job, a latency fix that saved a contract - anything where you can state the state before, what you did, and what moved afterwards.
Match the stack to the posting, once
Name the languages and infrastructure the job description names, in the sentence where you describe what you own. One pass is enough; the letter is not the place to repeat your resume's skills section.
Rewrite the last paragraph for each company
It is the only part that cannot be reused. Read the engineering blog, the changelog, or the job description's description of the team, and connect one real detail to something you have already done.
Keep only numbers you can defend in an interview
Every figure in this letter is the kind you will be asked about. If you cannot explain how the 40 percent was measured, use the qualitative version instead - a claim you cannot back is worse than no claim.
Listing every technology you have touched
A paragraph of language names reads as filler and tells a reviewer nothing about depth. The resume already carries the list; the letter has to carry the judgement.
Writing about what the team did
"We migrated" leaves the reviewer guessing at your share. Say what you led, what you built, and what you decided, and credit the team separately if it matters to you.
Restating the resume line by line
If the letter can be reconstructed from the resume, it has no reason to exist. Pick the one or two things the resume could not fit and expand those.
Opening with "I am writing to apply for" and stopping there
The sentence is harmless as a frame, but it cannot be the whole first paragraph. Put a fact behind it in the same breath, as this example does.
Use the ones that are true of you, in the sentences where you describe the work - not as a list bolted to the end. Matching a job description's vocabulary helps a keyword filter find you; it is not what convinces the person who reads the letter afterwards.
How long should a software engineer cover letter be?
One page, three to five paragraphs, roughly 250 to 400 words. This example sits at the top of that range because it carries a full project story. If your letter runs past a page, the fix is almost always to cut the second project rather than to shrink the margins.
Do engineering teams actually read cover letters?
It varies by company and there is no honest universal answer: some teams read every one, some screen on the resume alone, and plenty of applications never ask for a letter at all. The decision that makes sense is to write one when the form has a field for it, keep it short enough that skimming it costs nothing, and never let it be the only place an important fact appears.
Should I link to GitHub or a personal project?
Yes, if the link leads somewhere a stranger can understand in two minutes - a repository with a readme, a live demo, a write-up. Put the link in your resume's contact block and mention the project by name in the letter only when it supports the story you are telling.
What if I have no production experience yet?
Use the same structure with the largest thing you have built: a course project, an internship task, an open-source contribution. Describe the problem, your decisions, and what the result was, and be plain about the context. Reviewers discount the scale of a student project automatically; what they are reading for is whether you can reason about a system.